TRY OUT BIOLOGI CELLULAIR

1. Synaptic signaling involves

   A)  endocrine signals

   B)  paracrine signals

   C)  autocrine signals

   D)  neurotransmitters

2. Characteristics of intracellular receptors that regulate gene transcription include all of the following except

   A)  a DNA binding site

   B)  an extracellular binding site

   C)  a transcription activating domain

   D)  may be signaled by lipid soluble molecules

3. Cell surface receptors may be any of the following except

   A)  G protein linked

   B)  enzymic receptors

   C)  single-pass transmembrane proteins for neurotransmitters

   D)  chemically-gated ion channels

4. In the cAMP pathway, the G protein stimulates

   A)  phospholipase C

   B)  adenylyl cyclase

   C)  the endoplasmic reticulum

   D)  calmodulin

5. The ____ surrounds the cell like a belt, preventing the passage of substances between the cells.

   A)  gap junction

   B)  desmosome

   C)  hemidesmosome

   D)  tight junction

6. In most cases protein kinases

   A)  hydrolyze proteins

   B)  polymerize amino acids

   C)  stimulate adenylyl cyclase

   D)  bind cGMP

   E)  add phosphate groups to proteins

7. The receptor for nitric oxide (NO) is

   A)  intercellular

   B)  intracellular

   C)  extracellular

   D)  ultracellular

   E)  unicellular

8. In desmosomes, cadherins link to _______________ of an adjacent cell.

   A)  integrins

   B)  connexons

   C)  ras proteins

   D)  intermediate filaments

   E)  plasmodesmata

9. Which of the following are NOT involved in enzyme activation?

   A)  A-kinase

   B)  P nucleic acid

   C)  cAMP

   D)  nitric oxide

   E)  G protein

10. ________ junctions may protect a damaged cell through chemical gating.

   A)  Tight

   B)  Gap

   C)  Adherens

   D)  Occluding

   E)  Macular

11. Narrow gaps between nerve cells through which paracrine signals travel are called

   A)  desmosomes

   B)  calmodulins

   C)  synapses

   D)  integrins

   E)  maculae

12. _______________ is a common second messenger.

   A)  cAMP

   B)  cGTP

   C)  cMHC

   D)  cATP

   E)  cRNA

13. Paracrine signals

   A)  are long-lived with widespread effects

   B)  are short-lived, but with widespread effects due to cascades

   C)  are long-lived, but are acting locally

   D)  are short-lived with local effects

   E)  such as neurotransmitters, function only intracellularly

14. In anchoring junctions, cadherins are linked to

   A)  actin filaments in the cell's cytoskeleton

   B)  cell walls of adjacent cells in plants

   C)  connexons of its own and adjacent cells

   D)  extracellular matrices of adjacent cells

   E)  intracellular integrins of most cells

15. Intracellular receptors include those for

   A)  progesterone

   B)  vitamin D

   C)  cortisol

   D)  thyroid hormone

   E)  all of the above

16. Adherens junctions may involve

   A)  extracellular matrix

   B)  integrins

   C)  actin filaments

   D)  all of the above

   E)  none of the above

17. With respect to the plasma membrane, most enzymic receptors are

   A)  entirely internal

   B)  seven pass

   C)  entirely on the surface

   D)  multipass

   E)  single pass

18.A single-pass protein that acts as a "self" marker is

   A)  GTP

   B)  MHC

   C)  GMP

   D)  MCA

   E)  ADP

19. Binding of epinephrin to a G protein-linked receptor causes adenylyl cyclase to produce large amounts of

   A)  A-kinase

   B)  G protein

   C)  phospholipase C

   D)  inositol triphosphate

   E)  cAMP

20.Cell signals with short-lived local effects are called _______________

   A)  paracrine

   B)  apocrine

   C)  merocrine

   D)  holocrine

   E)  none of the above

21.Desmosomes are associated with ____________ junctions.

   A)  adherens

   B)  tight

   C)  anchoring

   D)  communicating

   E)  lymphomas

22.One protein kinase cascade begins with the phosphorylation of the

   A)  tap protein

   B)  gat protein

   C)  sat protein

   D)  ras protein

   E)  sap protein

23.Plasmodesmata

   A)  encircle cells of a tight junction like a belt

   B)  connect to intermediate fibers of the cytoskeleton

   C)  connect the cytoplasm of one plant cell to that of another

   D)  connect actin fibers of one cell to the extracellular matrix of another

   E)  is the name given to desmosomes of plant cells

24.The signalling molecules that travel the farthest are

   A)  endocrine

   B)  paracrine

   C)  neurotransmitter

   D)  intracellular

25.When a signal molecule arrives at a G protein-linked receptor, the G protein

   A)  becomes deactivated

   B)  binds to the signal molecule

   C)  becomes activated

   D)  binds with a Ca++

   E)  binds with calmodulin

26.Cells interact through the actions of chemical signals which either bind to receptors on the membrane or

   A)  pass through the plasma membrane

   B)  trigger responses from inside the cell

   C)  bind to intracellular receptors

   D)  activate receptors that bind to DNA

   E)  all of the above

27.Cell junctions that prevent small molecules from passing in between two cells are called

   A)  gap junctions

   B)  tight junctions

   C)  adhesions

   D)  plasmodesmata

   E)  all of the above

28.In some tissues subject to mechanical stress, special junctions called _______________ connect the cytoskeletons of adjacent cells.

   A)  cadherin junctions

   B)  tight junctions

   C)  stress junctions

   D)  anchoring junctions

   E)  gap junctions

29.Gap junctions are formed by

   A)  the fusion of plasma membranes to form a single membrane

   B)  the insertion of protein complexes that form tunnels between cells

   C)  protein hooks that extend into the membrane of adjacent cells

   D)  gaps in the cell wall of plants

   E)  none of the above

30.Plasmodesmata occur in

   A)  bacterial cells

   B)  all eukaryotic cells

   C)  plant cells

   D)  animal cells

   E)  the nucleus of the cell

31.A _______________ is a type of adhering junction between animal cells.

   A)  tight junction

   B)  plasmodesma

   C)  chemical synapse

   D)  gap junction

   E)  c and d, but not a and b

32.Protein kinases are enzymes that stimulate the production of hormones.

   A)  True

   B)  False

33.Hormones are relatively long lived signals that travel throughout the body. This type of signalling is called

   A)  paracrine signalling

   B)  synaptic signalling

   C)  autocrine signalling

   D)  endocrine signalling

   E)  direct contact

34.All of the following statements apply to G proteins except

   A)  G proteins transmit a signal from the cell surface to the interior of the cell

   B)  all G proteins have a similar structure

   C)  G proteins do not use second messengers but transmit the signal directly into the nucleus

   D)  G proteins act to amplify the signal creating a cascade response in the cell

   E)  G proteins underlie the actions of many medications

35.Receptors that are recognized by the immune system are

   A)  immunoglobulins

   B)  MHC proteins

   C)  T receptor

   D)  B receptor

   E)  all of the above

ANSWER

1. 1.   D      2. B     3. C    4. B    5.  D    6. E    7. B    8. D    9. B   10. B
2. 11. C    12. A    13. D   14.A   15. E   16.D   17. E   18.B   19.E   20.A
3. 21. C    22. D    23. C   24.A   25. C   26.E   27. B   28.D   29.B   30. C
4. 31. A    32. B    33. D   34. C  35. E